Automatic electric-arc-control mechanism.



H. M. BAKER, 1:. AUTOMATIC ELECHHC ARC CONTR OI. MECHANISM. APPLICATIONmm ocr. 2|. 1914.

1,239,759. Patented Sept. ll, 1917.

UNITED STATES PATENT OFFICE.

HAYDN' m. BAKER, m, or BROOKLYN, NEW YORK, Assmaoa 'ro Auotrs'ros'rnnanwsnn, an, or BROOKLYN, NEW some AUTOMATIC ELEOTRIC-ABC-CONTROLMECHANISM.

Specification of Letters Patent. Patented Sept, 11, 191 7.

Application tiled October 21, 1814. Serial No. 867,773.

To all whom it ma concern:

Be it known tint 1, Harms M. Barren, J12, a citizen of the UnitedStates, and resident of Brooklyn, in the county of Kings and State ofNew York, have invented certain new and useful Improvements in AutomaticEleetrie-Arc- Control Mechanism, of which the following is aspecification.

This invention relates to automatic. electrie'arc control mechanismdesigned to revide a device for feeding the carbons the are toward eachother to compensate for-- the material bu'rned away in the production.of the are.

The object of my invention is to provide a mechanism which will beresponsive to minute variations in the current occasioned by the varyingdistance between the carbons to automatically restore them to theirpositions of maximum brilliancy. My invention is desi ed particularlyfor use in connection wit i the are lamps employed in motion picture andstereoscopic itJPflltltllB and deal ed to perform the wor of the hand adustment commonly used in such 1am )8, and is arranged so as to permiteither the land adjustment or the power adjustment of thecarbons.

My improved control device is designed to be extremely sensitive and t0)er orm minute adjustments impossible to o tain by manual still therebyproducing a far steadicrlight than is obtainable with the constructionsnow on the market.

In the accompanying drawings I have illustrated a preferred form of myinvention. In the said drawings,

Figure 1 represents a side elevation of the entire device;

Fig. 2 shows the overnor device which will belater describe and Fig.3 isa detail view slio\ving ,.the connceting mechanism between the control'dc- Vlt'O and the adjusting shaft.

Referring now to Fig. l, i. represents the supporting bracket of thecanon holders of an are light such as employed in projection lamps,which bracket is supported in the usual manner on a standard 2. Swiveledto the bracket is a holder 3 alsoot usual construction which providesguiies for the rack bars 4 and 5 respectively, carrying the a per andlower carbons 4 and 5' of the light... The teeth of the rack-bars 4 and5 engage the opposite sides of a pinion carried by the shaft 6 rotatablymounted in a sleeve 7 projecting from the rear face of the part 3.

The mechanism so far described is the construction commonly used inlights of this character. In such apparatus a knob is attached to theshaft by which it may be rotated by hand when desired to adjust thecarbons toward or away from each other, according to the direction ofrotation.

My automatic control mechanism operates through the shaft 6 to adjustthe carbons and comprises a sleeve 8 fixedly attached to the shaft 6 andformed with a friction col-- lar at its inner end. Freol mounted on thesleeve 8 with its face in rictional engages ment with the collar is aworm gear 9, and enga 'ng the op osite face of the worm whee is a looseisk 10 capable of sliding movement on the shaft.

The sleeve 8 projects beyond the end of the shaft 6 andmounted on itsprojecting end on a cross pin 11 is a disk 12 having a slight rockingmovement, as will be obviods from an inspection of Fig. 3, and connectedto the disk 12 by two screws 13, Li, is a. milled knob 15 for handadjustment. The screw 18 is provided'with a milled head for handadjustment to ell'cct the clutching elf the worm wheel 9 against thecollar of t 0' use and permit the disengagement of the worm wheel forlmml adjustment. Both; screws are threaded in the disk 12 and bearagainst the disk 10, the screw 14 being provided with a nut whereby itmay be clamped in adjusted osition. By loosening the .screw 18 the isk12 will tilt sulliciently to also relieve the pressure of the screw 14,and when tightened both screws press .equally on the disk.

The worm gear!) is driven by means of a ve 8 when the power adjustmentis worm 16 rotatably mounted m a bracket 25 away from the shaft (l. Thebracket25 is clamped to a sleeve 26 loose on thesllaft adjacent thesleeve 8. The sleeve 26 is held against rotation by means of a fork 27pivotally connected to the sleeve and engaging a a fixed projection 28at its lower end.

The worm 10 is driven through'a-uni- .versal joint from a shaft ill"formed of two telescoping parts and connected at its lower end through asecond universal joint with the driven shaft of the speed control device14'. This'devicc per se forms no part of the present invention beingcovered by my copending application, Serial No. 829,779, filed April 6,19H, but for the sake of clearness I have shown its essentials in Fig.

As shown in Fig. 2 and more in detail in the drawings in said copendingapplication, 15" represents the driven shaft to be constantly driven and16" represents the driven shaft which is connected to the driving shaftto drive the clutch whenever the speed of the driven shaft exceeds apredetermined maximum. To effect this connection the driving shaft isprovided with a worm, not shown, but driving the worm gear 17 loose onthe driven shaft and provided with a beveled gear which connects througha planet gear 18 with a second beveled gear fast to the shaft 10'. Theplanet gear 18 is supported by a cage 19 which is free to rotate on theshaft 16' except when it is locked against rotation by a centrifugalmechanism driven from the driving shaft. This mechanism comprisescentrifugal weights 20 whose outward movement upon the excessive speedof the shaft thrusts a awl 21 into engagement with looking proectionscarried by the cage '19. When the pawl is disengaged the cage 19revolves idly around the shaft 16' without driving the shaft, but whenthe cage is locked by the excessive speed of the driving shaft, thepinion 18 acts as an idler for transmittin the full power of the shaft15" to the sha 16, as will be readily understood. As explained in myco-pending application above referred to, this mechanism. is extremelysensitive to the slightest change in speed of the shaft 15', and thedevice can be adjusted to vary the critical speed at which the drivingconnection .takes place. For combining this mechanism with an electricare 1 conneet the shaft 16 asdescrihed to the carbon adjusting shaft andthe driven shaft 15 to the shaft of an electric motor 22 preferablysupported as shown on the rod 23 carried in a suitable base plate andproviding a support for the casing of the speed controller 14', wherebythe motor shaft and control shaft may be maintaincdinalinement.

The electric mdtor 22 is connected as a shunt across the terminals ofthe lamp, or to the wires thereto. Assuming operating conditions. acertain size of arc-or gap between the carbons-will impress a certainvoltage on the motor terminals resulting in a certain speed of themotor, a larger gap increasing this voltage and motor speed, a snmllerone rediicing the same.

'lhe adjusting screw 24, as described in my previous application whichprojects from the end of the cover of the controller, regulates thecriticalspeed of the latter, which maybe set to represent the motorspeed which will be produced by any desired size of arc.

The operation of' the mechanism will be understood from the foregoingdescription. As the carbons lmrn away in the production of the light andthe gap' of the arc gets larger the resistance through the carbons willbe increased thereby-causing more of the current to he shunted throughthe electric motor with a corresponding increase in speed of the motor.As the normal speed of the motor is just below the critical speed of thecontrolling device. the slight inc ease. in speed will cause the weights20. to'fly out aml operate the pawl 21 thereby connecting the drivenshaft of the device to the shaft 16, rotating the shaft in the directionto turn the adjusting, shaft through the connection described to bringthe carbons nearer together. Bringing the carhons closer together ofcourse reduces the resistance through the are which will reduce thecurrent through the motor so that the speed of the motor falls and whenthe carbons are back to their position of maxinnnn brilliancy the speedof the motor shaft will once more be below the critical speed of thespeed controlling device, and the locking p'awl will release the cagethereby disconnecting the adjusting mechanism from the motor shaftleaving the carbons in thetr properly adjusted position.

As explained above the mechanism of the speed controller is verysensitive in operation, so that an increase of resistance of the are,imperceptible to the eye, willcause the adjusting mechanism to res vondand give a slight movement to the ear ons.

As described in my copending application above referred to my improved seed control mechanism may be double acting in its operations, that is.it may be designed to connect the power shaft to the driven shaft forreverse operation upon the speed of the power shaft falling below apredetermined minimum, which mhle acting mechanism while not necessaryfor an are light under ordinary conditions would beuseful to prevent thecarbons bein brought too close together through accitental fluctuationsin the current not under the control of the operator.

Having thus described my invention, what I claim and desire to secure byLetters Pat ent is: y j

1. In electric arc control mechanism, the combination comprising a pairof electrodes adjustable toward and from each other, gearing foradjusting said electrodes, a normally stationary shaft for actuatingsaid 'aring, means for operating said gearing iy haml. including asleeve fixedly mounted upon said shaft aml having a frictional rollar atits inner end, a worm gear loosely mounted on said sleeve, adapted tofrictionnlly engage with its lateral face the lateral face of saidcollar, a disk member also lmsely mounted on said sleeve and slidablelhcl'con, arrun ed to normally engage the opposite latera face of saidworm gear, a second disk member capable of limited rocking movement butincapable of longitudinal movement, mounted on said sleeve beyond thefirst disk member, a single adjusting screw for frictionally connectingand dis-- connecting said disk members 0 eratively with said worm gear,and means or actuating said shaft by hand when said disk members areoperatively disconnected from said worm gear.

2. In electric arc. control mechanism, the combination comprising a airof electrodes each provided with a ruckar, a pinion for relativelyadjusting the said electrodes, a

normally stationary shaft for actuatin' said pinion in circuit with saidelectr es, a shaft for operating said pinion and provided with a hxedsleeve halving a friction colenga lar at its inner end a worm looselymounted on said sleeve and adaited to frictionally with its lateral lacethe lateral face of said collar, a disk member also loosely and slidablymounted on said sleeve arranged to normally engage the ()PFositc lateralface of saidworm, a second dis member capable of limited rockingmovement, but incapable of slidablemovement mounted on said sleevebeyond the first disk member, a single adjusting screw for frictionallyoperatively connecting, and disconnecting the said disk members withsaid worm and means for actuating said shaft by hand when said diskmembers are operatively disconnected from said worm.

Si ed at New York, in the county of New ork and State of New York, this19th day of October, 1914.

HAYDN M. BAKER, J n.

Witnesses;

L. E. Jomzs'ron, M. E. Evnmzw.

